There's no prepay penalty in the US. I got a fixed rate at 5% on my current house and currently pay 3% due to having taken out new loans to pay off the old one (a.k.a refinancing).
A 30 year rate fix with no prepay penalty is incredibly borrower friendly because you can (nearly) always take advantage of lower interest rates, but don't have to worry about your rate ever going up.
I honestly don't know. The way many restrictions work in the US though is that legally is on a state-by-state basis, but the main driver is whether or not Fannie Mae (and similar federal entities) will underwrite the loan. That's where the 30 year maximum term, and 80% loan-to-value limits come from
American mortgages are also designed to pay out disproportionately more interest up front, and much of the cost of the loan is also paid directly at closing as up front fees.
Ex: closing costs for new mortgage in my area average around 5k.
A 30 year rate fix with no prepay penalty is incredibly borrower friendly because you can (nearly) always take advantage of lower interest rates, but don't have to worry about your rate ever going up.